<template>
  <div class="wrap" ref="wrap">
    <div 
      class="item"
      v-for="(item, index) in items" 
      :style="{ height: item.height }" 
      :key="index"
    ></div>
  </div>
</template>

<script>
export default {
  data: () => {
    return {
      items: [
        { height: '100px' },
        { height: '50px' },
        { height: '200px' },
        { height: '250px' },
        { height: '80px' },
      ]
    }
  },
  mounted() {
    this.$nextTick(() => {
      console.log(this.$refs.wrap)
      const wrap = this.$refs.wrap
      for(let i = 0; i < wrap.children.length; i++){
        console.log(wrap.children[i].offsetHeight)
      }
    })
  }
}
</script>

<style>
.item{
  width: 100px;
  background: red;
  margin-bottom: 10px;
}
</style>